Arrangement and method for controlling service activation on a mobile terminal

ABSTRACT

An arrangement and method in a wireless communication network provides users with full control of service management, defines how a user can enter or leave services, and defines dependencies between services. A mobile terminal initiates establishment of a group and creates a unique groupID. The terminal sends invitations to other terminals to join the group and includes the unique groupID and a service feature tag for a desired service. The terminal will not request a service if it is incompatible with a service already running. Terminals that receive invitations store the groupID and service feature tags. These parameters are used to send acceptances or rejections, and to join later or leave a service.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/305,304 filed Feb. 16, 2009, now U.S. Pat. No. 8,150,383, which is a371 of International Application No. PCT/IB2006/001659, filed Jun. 20,2006, the disclosures of which are fully incorporated herein byreference.

TECHNICAL FIELD

This invention relates to mobile communication systems. Moreparticularly, and not by way of limitation, the invention is directed toan arrangement and method for controlling activation and deactivation ofservices on a mobile terminal.

BACKGROUND

Group communication services are becoming increasingly popular. Manyservices providing group communications such as Microsoft Network (MSN),Skype, or Yahoo have traditionally operated only with personalcomputers, but are now moving to mobile devices. To date, there havebeen activities regarding service manipulation on the network side (forexample, service composition and SIP servlets), but little or noactivity on the terminal side. The network solutions do not give theuser full control of service management. No rules exist that define howa subscriber can enter or leave services, and there are no rulesdefining dependencies between services.

What is needed in the art is an arrangement and method for manipulatingservices that overcomes the shortcomings of the prior art. The presentinvention provides such an arrangement and method.

SUMMARY

The present invention provides an arrangement and method that providesusers with full control of service management, defines how a user canenter or leave services, and defines dependencies between services.

Thus in one aspect, the present invention is directed to a method ofactivating a desired service on a mobile terminal participating in afirst group. The method includes determining whether activation of thedesired service on the mobile terminal would conflict with a servicerunning on other mobile terminals in the group. If activation of thedesired service on the mobile terminal would conflict with the runningservice, the method determines whether the running service can bestopped. If the running service cannot be stopped, the method sends anotification to the mobile terminal that the desired service cannot beactivated. If the other service can be stopped, the method stops theother service and activates the desired service on the mobile terminal.

In another aspect, the present invention is directed to a method ofactivating a desired service on a mobile terminal participating in afirst group. The method includes determining whether the desired serviceis a service that cannot be activated in more than one group at a time.If so, the method determines whether the desired service is running in asecond group. If so, the method stops the desired service in the secondgroup. The method also determines whether a second service is running inthe first group that is incompatible with the desired service. If so,the method sends a notification to the mobile terminal that the desiredservice cannot be activated. If there is not a second service running inthe first group that is incompatible with the desired service, themethod activates the desired service on the mobile terminal.

In another aspect, the present invention is directed to a method ofdeactivating a service on a mobile terminal participating in a group.The method includes determining whether the service is a one-to-manyservice. If not, the mobile terminal leaves the service. If the serviceis a one-to-many service, the method determines whether the mobileterminal started the service. If so, the method stops the service. Ifthe mobile terminal did not start the service, the mobile terminalleaves the service while other members of the group continue to run theservice.

In another aspect, the present invention is directed to a method in awireless communication network for establishing a user group thatcomprises a plurality of mobile terminals, and running a conferenceservice. The method includes the steps of initiating the conferenceservice by a first mobile terminal; setting up by the network, an emptyconference with the first mobile terminal; inviting by the first mobileterminal, a second mobile terminal in the network to join theconference; and joining the conference by the second mobile terminal.This is followed by notifying the first mobile terminal that the secondmobile terminal has joined the conference; and notifying the secondmobile terminal that the conference includes the first mobile terminaland the second mobile terminal.

In another aspect, the present invention is directed to an arrangementin a wireless communication network for providing users with control ofservice management. The arrangement includes means for enabling a firstuser to establish a group; means for enabling the first user to invite aplurality of other users defined by the first user to join the group;and means for enabling a user to start a service within the group. Theservice starting means ensures that the service does not conflict withany other services already running within the group or in other groups.The arrangement also includes means for enabling the first user toinvite a plurality of other users defined by the first user to subscribeto the service.

In another aspect, the present invention is directed to a mobileterminal for providing a user with control of service management in awireless communication network. The mobile terminal includes means forinitiating establishment of a group of mobile terminals; means forcreating a unique group identifier for the group; and means for sendinginvitations to other mobile terminals to join the group. The invitationsinclude the unique group identifier and a service feature tag. Themobile terminal also includes means for storing unique group identifiersand service feature tags received in invitations from other mobileterminals; and means for sending acceptances to invitations to joinother groups received from other mobile terminals. Through use of themobile terminal, the user may join and leave an ongoing service any timeafter being invited to join. Even if the invitation was initiallyrejected, the user may join later.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following section, the invention will be described with referenceto exemplary embodiments illustrated in the figures, in which:

FIG. 1 is a flow chart illustrating the steps of an exemplary procedurefor service activation in Group A;

FIG. 2 is a flow chart illustrating the steps of an exemplary procedurefor service deactivation;

FIGS. 3A-3B are portions of a signaling diagram illustrating the flow ofmessages in an exemplary procedure for starting a group;

FIG. 4 is a signaling diagram illustrating the flow of messages in anexemplary procedure for leaving a group;

FIG. 5 is a signaling diagram illustrating the flow of messages in anexemplary procedure for adding a new service to a group that currentlyis running a service;

FIG. 6 is a signaling diagram illustrating the flow of messages in anexemplary procedure for inviting a new participant to join an existinggroup;

FIG. 7 is a signaling diagram illustrating the flow of messages in anexemplary procedure for rejecting an invitation to join an existinggroup; and

FIG. 8 is a signaling diagram illustrating the flow of messages in anexemplary procedure for a new participant to utilize a stored groupIDand service FT to join an existing group.

DETAILED DESCRIPTION

In this description, the 3GPP IMS architecture and the IETF protocol SIPis used as a foundation for the application. The invention is howevernot restricted to using 3GPP IMS and SIP.

In the present invention, mobile terminals maintain a matrix-basedrepresentation of services and subscriber groups for the mobileterminal, together with defined procedures for activation anddeactivation of the services. An example of such a representation isshown below in Table 1. Columns in the table show the subscriber groupscurrently running in the terminal, and rows show the services supportedby the terminal (i.e., capabilities). Symbols in the table have thefollowing meanings:

M—the service is active in the group and I am a participant.

G—the service is active in the group but I am not a participant.

X—the service is active in the group but my subscription does not allowme to use it.

TABLE 1 Service mapping example Group Service Group A Group B Group CText chat M M M Voice chat G M Live video M Video share Live TV Gaming MWhiteboard X

Different types of services and interactions between them are definedfrom the terminal perspective. Using the table representation, it can bereadily determined which services are currently running in each group,and whether the running services are consistent. The mechanisms fordealing with different types of services are common for all services,and thus the description does not refer to any specific service but to ageneric one referred as “Service1”.

The following definitions of different types of services are utilizedherein:

Default service—a service that starts upon group creation and isdestroyed when the group is closed. An example of such service is textchat.

User-active service—a service currently running and utilized by theuser. Such services are marked by M in Table 1.

Group-active service—a service currently running by the group but not bythe user. Such services are marked by G in Table 1.

Single service—a service that cannot be user-active in more than onegroup at a time. An example of such service is voice chat.

Mutually exclusive services—services that are not allowed to begroup-active in the same group. Examples of such services are live videoand whiteboard.

One-to-many service—a service where its creator is in control of themedia stream and other participants are the receivers of the media.Examples of such services are live video and video share.

Unsubscribed service—a service that is not allowed to run since the usersubscription does not cover it. X in Table 1 marks such services.

Unsupported service—a service that cannot run due to limitations of theuser terminal.

In the following sections, procedures are defined for activating anddeactivating services. A user is only in control of services running onhis terminal, and can create, join, leave, or stop such services. It isassumed that the target terminal has at least one group communicationrunning, which implies that the user runs at least the default servicein each of the created groups.

FIG. 1 is a flow chart illustrating the steps of an exemplary procedureperformed by a mobile terminal for service activation in Group A. Thereare four conditional statements involved in service activation, whichcheck the service nature and determine whether the service is inconflict with services running in the same group or on the sameterminal. The last conditional statement in the diagram decides if theservice will be started (i.e. it was not running in Group A) or joined.

At step 11, it is determined whether the service is a single service,that is, a service that cannot be user-active in more than one group ata time. If not, the process moves to step 14. If the service is a singleservice, the process moves to step 12 where it is determined whether theservice is running in some other group such as Group B. If not, theprocess moves to step 14. If the service is running, for example inGroup B, the process moves to step 13 where the service is stopped inGroup B.

At step 14, it is determined whether there are any mutually exclusiveservices running in Group A. If so, the process moves to step 15 whereit is concluded that the new service cannot be started. If there are notany mutually exclusive services running in Group A, the process moves tostep 16 where it is determined whether the service is passive in GroupA. If so, the process moves to step 17 where the service is started. Ifthe service is not passive in Group A, the process moves to step 18where the user joins the service.

FIG. 2 is a flow chart illustrating the steps of an exemplary procedureperformed by a mobile terminal for service deactivation. When a userleaves a service, it is important to know whether the service is aone-to-many service and whether the person leaving the service is theone who started it. In this case the service (for example live video)will be deactivated for all group participants. If the user did notstart the service, the user can leave the service and the rest of thegroup can continue running it.

At step 21, it is determined whether the service is a one-to-manyservice, that is, a service where its creator is in control of the mediastream and other participants are the receivers of the media. If not,the user leaves the service at step 24. If the service is a one-to-manyservice, the process moves to step 22 where it is determined whether theuser attempting to leave the service is the user who activated theservice. If not, the user leaves the service at step 24. If the userattempting to leave the service is the user who activated the service,the process moves to step 23 where the service is deactivated for all ofthe users.

An important principle of this invention is the manner in which serviceswithin groups are addressed. To facilitate joining or leaving a servicewithin a group at any time, the invention utilizes a mechanism withdouble addressing. It is a useful feature allowing, for example, joiningand leaving a voice conversation at any time. Each service that isactive in a group is addressed using two parameters:

a) Service feature tag (FT); and

b) Unique group ID.

Together, these two parameters provide a unique address that can be usedfor joining a given service within a given group. Upon receiving anInvite message, the two parameters are stored in the user terminal. Thiskind of addressing also enables an entire group to be closed at once byusing the unique group ID. By using the service feature tag instead, aspecific service may be left (or stopped) in any group.

At any time, any group member can add group participants to a group. Thefollowing sections describe the procedures for activating anddeactivating services, creating groups, joining services in a group, andleaving services in a group.

FIGS. 3A-3B are portions of a signaling diagram illustrating the flow ofmessages in an exemplary procedure for starting a group. In thisexample, a user utilizing User Equipment-A (UE-A) 31 starts a group byinviting UE-B 32 and UE-C 33 to join a default service, Service-1. FIGS.3A-3B illustrate the setup for UE-B, and thereafter, the setup for UE-Cis the same. Referring to FIG. 3A, before sending the initial INVITEmessage 34, the user UE-A determines whether the service can be startedon its terminal according to the procedures described in the previoussection. The initial INVITE message, labeled INVITE (1), has thefollowing arguments:

-   -   To: sip:service1-factory@domanA.org    -   Accept-contact: “Service1”

The INVITE message passes through Call State Control Function (CSCF-A)35 to a Conference Factory 36 for Service1. The Conference Factorycreates a conference instance at step 37 and reserves media resources atstep 38. The Conference Factory then sends a SIP 200 OK message 39through the CSCF-A to UE-A 31. The 200 OK message, labeled 200 OK (2),has the following format:

-   -   To: sip:b@domainB.org    -   From: service1-factory@domainA.org    -   Contact: sip:conf77@service1-factory.domainA.org

At step 40, the UE-A 31 creates a unique group ID in response, which issent to all group participants via a REFER message 41. The REFER messagesent to UE-B, labeled REFER (3), has the following format:

-   -   To: sip:b@omainB.org    -   From: a@domainA.org    -   Contact: a@domainA.org    -   Refer-To: conf77@service1-factory.domainA.org; is Focus;        method=INVITE    -   Referred-by: sip: a@domainA.org    -   Subject: GR345

After receiving the REFER message 41, UE-B stores the service featuretag (FT) (conf77@service1-factory.domainA.org) and the unique groupID(GR345) at step 42. Users may utilize these identifiers later to jointhe service in the group. UE-B then sends a 202 Accepted message 43 toCSCF-B 44, accepting the REFER message. UE-B then sends an INVITEmessage 45 through CSCF-B and CSCF-A to a Focal Point 49 associated withService-1. The INVITE message, labeled INVITE (4) has the followingformat:

-   -   To: sip:conf77@service1-factory.domainA.org    -   From: sip: b@domainB.org    -   Referred-by: sip:a@domainA.org

Referring to FIG. 3B, at step 46, UE-A is notified that UE-B has joined.At step 47, the notification service is performed for UE-B. The processis then repeated at step 48 for UE-C.

FIG. 4 is a signaling diagram illustrating the flow of messages in anexemplary procedure for leaving a group. In this example, UE-B 32 leavesthe group consisting of UE-A 31, UE-B 32, and UE-C 33. The processstarts when UE-B sends a Subscribe message 51 through CSCF-B 44 andCSCF-A 35 to a Focal Point 49. A validity period in the Subscribemessage is set to zero (0). The Focal Point then sends a Notify message53 back to UE-B by the same route. The Notify message indicates thatUE-B is unsubscribed, i.e., will not receive any further notificationsabout group events. UE-B then sends a BYE message 54 to the Focal Point.At step 55, the Focal Point works with a Multimedia Resource FunctionProcessor (MRFP) 56 to release network resources associated with UE-B.At step 57, the Focal Point notifies UE-A that UE-B has left, and atstep 58, the Focal Point notifies UE-C that UE-B has left. The FocalPoint may retain the address for UE-B so that the Focal Point mayoptionally send a notification to UE-B at a later time if thegroup/service is deactivated, and is no longer available to be joined.

FIG. 5 is a signaling diagram illustrating the flow of messages in anexemplary procedure for adding a new service (Service-2) to a group thatcurrently is running a service (Service-1). In this example, UE-A 31 isadding Service-2 and inviting UE-D 61 to join. At step 62, it is notedthat the precondition for this procedure is that Service-1 (e.g. textchat) is running in the group.

UE-A 31 starts the process by sending a REFER message 63 to the group.For simplicity, only the REFER message to UE-D 61 is shown. Note thatbefore sending this message, a consistency check is performed todetermine whether Service-2 is in conflict with Service-1 running in thesame group or on the same terminal. The REFER message has the followingformat:

-   -   To: sip:d@domainD.org    -   From: a@domainA.org    -   Contact: a@domainA.org    -   Refer-To: conf77@service2-factory.domainA.org; is Focus;        method=INVITE    -   Referred-by: sip: a@domainA.org    -   Subject: GR345

After receiving the REFER message 63, UE-D stores the service address(conf77@service2-factory.domainA.org) and the unique groupID (GR345) atstep 64. UE-D then sends a 202 Accepted message 65 through CSCF-A 35 toUE-A, accepting the REFER message. UE-D then sends an INVITE message 66through CSCF-A to a Focal Point 67 associated with Service-2. The INVITEmessage has the following format:

-   -   To: sip:conf77@service2-factory.domainA.org    -   From: sip: d@domainD.org    -   Referred-by: sip:a@domainA.org

At step 68, UE-A is notified that UE-D has joined, and UE-D is notifiedthat it has joined the group for Service-2. At step 69, the setupprocess is then repeated for the other group members. At step 70,Service-1 and Service-2 are both running in the group.

FIG. 6 is a signaling diagram illustrating the flow of messages in anexemplary procedure for inviting a new participant to join an existinggroup. In this example, UE-A 31 is inviting UE-D 61 to join. The groupruns two different services, and the UE-D receives a REFER for eachservice separately and can choose to accept or reject each service. Inany case, the service address is stored on the terminal of the invitedparticipant.

UE-A 31 starts the process by sending a first REFER message 71 to UE-D61. The REFER (1) message invites UE-D to join the group to participatein Service-1. After receiving the REFER (1) message, UE-D stores theservice FT (conf77@service1-factory.domainA.org) and the unique groupID(GR345) at step 72. UE-D then sends a 202 Accepted message 73 throughCSCF-A 35 to UE-A, accepting the REFER (1) message. UE-D then sends anINVITE message 74 through CSCF-A to the Focal Point 49 associated withService-1.

UE-A 31 continues the process by sending a second REFER message 75 toUE-D 61. The REFER (2) message invites UE-D to join the group toparticipate in Service-2. After receiving the REFER (2) message, UE-Dstores the service FT (conf77@service2-factory.domainA.org) and theunique groupID (GR345) at step 76. UE-D then sends a 202 Acceptedmessage 77 through CSCF-A 35 to UE-A, accepting the REFER (2) message.UE-D then sends an INVITE message 78 through CSCF-A to the Focal Point67 associated with Service-2. At step 79, UE-A is notified that UE-D hasjoined, and UE-D is notified that it has joined the group for Service-1and/or Service-2. At step 80, the other group members are notified thatUE-D has joined the group for Service-1 and/or Service-2.

FIG. 7 is a signaling diagram illustrating the flow of messages in anexemplary procedure for inviting a new participant to join an existinggroup, and rejecting the invitation by the invited participant. In thisexample, UE-A 31 is inviting UE-D 61 to join, and UE-D declines. Notethat even in the case of a rejection, the group ID and the service FTare stored on the participant's terminal allowing him to join later.

At step 81, it is noted that the precondition for this procedure is thatgroup communication between UE-A 31 and UE-B 32 is ongoing, UE-A startsthe process by sending a REFER message 82 via CSCF-A 35 and CSCF-B 44 toUE-D 61. The REFER (3) message invites UE-D to join the group toparticipate, for example, in Service-1. After receiving the REFER (3)message, UE-D stores the service FT(conf77@service1-factory.domainA.org) and the unique groupID (GR345) atstep 83. UE-D then sends a 603 Decline message 84 via CSCF-B and CSCF-Ato UE-A, declining to join. It is noted at step 85 that although UE-Dhas declined, UE-D may join later utilizing the stored groupID andservice FT.

FIG. 8 is a signaling diagram illustrating the flow of messages in anexemplary procedure for a new participant to utilize a stored groupIDand service FT to join an existing group. In this example, UE-B 32 joinsan existing group in which UE-A 31 and UE-D 61 are running Service-1.UE-B was previously invited to join the group, but either rejected theinvitation or joined the group and then left. Now UE-B utilizes thestored groupID and the service FT currently running in the group to jointhe group and subscribe to Service-1.

At step 91, it is noted that the precondition for this procedure is thatUE-A 31 and UE-D 61 are running Service-1 in a group. UE-B 32 starts theprocess by sending an INVITE message 92 via CSCF-B 44 and CSCF-A 35 tothe Focal Point 49 for Service-1. The INVITE message includes the uniquegroupID, which UE-B previously stored when UE-B was first invited to thegroup. The Focal Point reserves media resources with MRPF 56 at step 93.The Focal Point then sends a Notify message 94 to CSCF-A, which sendsnotifications 95 and 96 to the group members UE-A and UE-D indicatingthat UE-B has joined the group.

Once UE-B 32 has joined the group, he can choose which services withinthe group he would like to participate in. Having decided to participatein Service-1, UE-B sends a Subscribe message 97 via CSCF-B 44 and CSCF-A35 to the Focal Point 49 for Service-1. The Subscribe message includesthe service FT for Service-1, which UE-B previously stored when UE-B wasfirst invited to the group. At step 98, a notification service isconducted to notify UE-B that UE-A 31 and UE-D are running Serivce-1. Atstep 99, it is noted that the postcondition for this procedure is thatUE-A, UE-B, and UE-D are running Service-1 in the group.

Those skilled in the art will readily appreciate that the presentinvention may be implemented using either hardware, or software, orboth, and further, software implementations may vary using differentlanguages and data structures.

The present invention may of course, be carried out in other specificways than those herein set forth without departing from the essentialcharacteristics of the invention. The present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive. All changes coming within the meaning and equivalency rangeof the appended claims are intended to be embraced therein.

The invention claimed is:
 1. A method in a wireless communicationnetwork for establishing a user group conference that comprises aplurality of mobile terminals, and running a conference service withinthe user group conference, said method comprising: initiating theconference service by a first mobile terminal by sending an Invitemessage from the first mobile terminal to the network, the Invitemessage identifying the conference service, thereby enabling the networkto route the Invite message to a conference factory for the identifiedconference service; setting up by the network, an empty conference withthe first mobile terminal, wherein the conference factory returns to thefirst mobile terminal, a service feature tag identifying the conferenceservice and providing an address of the conference factory; inviting bythe first mobile terminal, a second mobile terminal in the network tojoin the user group conference and the identified conference service,wherein the first mobile terminal sends to the second mobile terminal, adouble address comprising the service feature tag and a unique groupidentifier for the user group conference; utilizing the unique groupidentifier by the second mobile terminal to join the user groupconference, wherein the second mobile terminal sends a second invitemessage to a focal point associated with the identified conferenceservice, the second invite message including the unique groupidentifier; and utilizing the stored service feature tag by the secondmobile terminal to subscribe to the identified conference service;notifying the first mobile terminal that the second mobile terminal hasjoined the user group conference; and notifying the second mobileterminal that the user group conference includes the first mobileterminal and the second mobile terminal.
 2. The method according toclaim 1, wherein the step of setting up an empty conference with thefirst mobile terminal includes: creating a conference instance betweenthe conference factory and a focal point associated with the conferenceservice in response to receiving the invite message from the firstmobile terminal; and reserving media resources for the first mobileterminal.
 3. The method according to claim 2, wherein the step ofinviting the second mobile terminal to join the conference includessending a refer message from the first mobile terminal to the secondmobile terminal, said refer message inviting the second mobile terminalto join the conference, wherein the refer message includes the doubleaddress comprising the service feature tag and the unique groupidentifier.
 4. The method according to claim 3, further comprising,after sending the refer message to the second mobile terminal, the stepsof: storing in the second mobile terminal, the double address comprisingthe service feature tag and the unique group identifier; initiallydeclining by the second mobile terminal, to join the conference service;and at a later time: utilizing the unique group identifier by the secondmobile terminal to join the group; and utilizing the stored servicefeature tag by the second mobile terminal to subscribe to the conferenceservice.
 5. The method according to claim 1, wherein the step ofutilizing the stored service feature tag by the second mobile terminalto subscribe to the conference service includes sending a subscribemessage from the second mobile terminal to the focal point associatedwith the conference service, said subscribe message including the storedservice feature tag.
 6. An arrangement in a wireless communicationnetwork for providing users with control of service management, whereineach user is served by an associated Call State Control Function (CSCF)in the network, said arrangement comprising a Focal Point incommunication with a Conference Factory and a Multimedia ResourceFunction Processor (MRFP), wherein the Focal Point and the ConferenceFactory are associated with an identified conference service, whereinthe arrangement is configured to: enable a first user to establish agroup by sending a first Invite message from the first user to thenetwork, the first Invite message identifying the conference service,thereby enabling the network to route the first Invite message to theConference Factory for the identified conference service; enable thefirst user to invite a plurality of other users defined by the firstuser to join the group and to subscribe to a conference service to beprovided within the group, wherein invitations sent by the first userinclude a double address comprising a unique group identifier and aservice feature tag identifying the conference service; enable the firstuser to start the conference service within the group, wherein thearrangement is configured to ensure that the service does not conflictwith any other services already running within the group or in othergroups; wherein to enable the first user to invite the plurality ofother users defined by the first user to join the group, the arrangementincludes a mobile terminal adapted to send a refer message to theplurality of other users defined by the first user, said refer messagecontaining the double address comprising the unique group identifier andthe service feature tag, wherein the service feature tag provides anaddress of the conference factory; enable each of the other users toutilize the unique group identifier to join the group, wherein the FocalPoint is configured to receive from each of the other users, a secondInvite message including the unique group identifier; and enable each ofthe other users to utilize the stored service feature tag to subscribeto the conference service.
 7. A mobile terminal for providing a userwith control of service management in a wireless communication network,wherein the mobile terminal is configured to: initiate establishment ofa group of mobile terminals by sending an Invite message from the mobileterminal to the network, the Invite message identifying a conferenceservice, thereby enabling the network to route the Invite message to aconference factory for the identified conference service; create aunique group identifier for the group; send invitations to other mobileterminals not included in the group of mobile terminals to join thegroup, said invitations including a double address comprising the uniquegroup identifier and a service feature tag identifying a conferenceservice to be provided within the group, wherein the unique groupidentifier enables each of the other mobile terminals to join the groupby sending a second Invite message including the unique group identifierto a focal point associated with the identified conference service, andto utilize the stored service feature tag to subscribe to the conferenceservice; store double addresses comprising unique group identifiers andservice feature tags received in invitations from the other mobileterminals; and send acceptances to invitations to join other groupsreceived from the other mobile terminals.
 8. The mobile terminalaccording to claim 7, wherein the mobile terminal is also configured tosend rejections to invitations to join other groups received from theother mobile terminals.
 9. The mobile terminal according to claim 8,wherein the mobile terminal is also configured to leave a grouppreviously joined.